A prisoner went on hunger strike to secure a vegan diet in Northern Ireland, official files have revealed.

The man was an inmate at HMP Belfast on the Crumlin Road and the year was 1987.

A Northern Ireland Office (NIO) folder disclosed by the Public Records Office of Northern Ireland (Proni) showed that an inmate wanted to secure a more balanced vegan diet.

The principal medical officer in December 1987, MC Dickson, wrote: “In the past, when (name redacted) was previously a prisoner in both Maze and Magilligan, his constant demand was for raw vegetables.

“I can do no better than refer you to comments made on file by the late Dr Ross that Man is not a ruminant and thereby does not have the physical capacity in his stomach to break down the cellulose wall of the vegetables and thereby release the nutritious elements present.

“Rightly or wrongly, I feel prisoners, or indeed anyone else for that matter, should clearly understand that diets taken to extremes can have consequences which are not immediately predictable or controllable.”

He compared it to hunger striking prisoners, when inmates were warned of the possible consequences for their health.

In the context of a prison environment, why should vegetarianism be treated any differently, bearing in mind the potential consequences?

“We cannot predict what deficiency states or when they will arise or indeed if they will arise.”

He said he could not agree to additionally providing vitamin supplements on a “guestimate” basis for what the authorities thought may happen.

“As we know, prisoners have got obsessions about their health; for example, fitness training, multiplicity of complaints etc.

“I think we would be in very grave danger of providing any other reason for going on a vegetarian diet, namely that they would also get added vitamins.”

Elsewhere in the archives, the director of the Forensic Science Laboratory was asked for his opinion on the “potential misuse” of bananas in 1990.

An official paper on his comments said: “In his reply, he takes the view that any claims regarding the psychedelic properties of smoking dried banana skins are psychological rather than real.

In fact, in a further discussion, he said that there are more known psycho-active materials present in tea or coffee compounds than in banana skins.

“In these circumstances we have no security objections to the introduction of bananas into the prison diet.”